Frequently asked questions about giraffe

Recent research by GCF and partners has shown that there are four different species of giraffe and not only one as previously assumed. Two of these species have two and three distinct subspecies respectively. All species and their subspecies live in geographically distinct areas throughout Africa and while some of these have been reported to cross-bread in zoos, there is no evidence that this occurs regularly in the wild.

These recent findings are based on a long-term effort, spearheaded by GCF in collaboration with BiK-F Senckenberg Museum, Frankfurt, Germany and partners, to unravel the mystery of giraffe genetics. GCF and partners collected almost 200 DNA samples from most major giraffe populations across Africa. These new finding will inform the future of giraffe conservation throughout Africa.

Three decades ago, in the 1980s, the total number of all giraffe in Africa was estimated at approximately 155,000 individuals. The International Union for the Conservation of Nature (IUCN) Species Survival Commission (SSC) Giraffe & Okapi Specialist Group and GCF estimate the current Africa-wide giraffe population to be less than 100,000 individuals. This is a drop of almost 40%. In some areas traditionally regarded as prime giraffe real estate, numbers have dropped by more than 95%. Read more about giraffe numbers here.

Giraffe numbers have dropped significantly during recent years and giraffe are under a lot of pressure. IUCN SSC Giraffe & Okapi Specialist Group in collaboration with GCF has recently submitted updated assessments of giraffe numbers to the IUCN Red List – so stay tuned. With the exception of Angolan, South and West African giraffe, all other subspecies are either decreasing or unstable. Habitat loss, habitat fragmentation, habitat degradation, poaching, and ultimately human population growth continue to impact on giraffe and their habitat across the continent.

While recent research has shown that there are in fact four giraffe species and not only one, the IUCN currently still recognises giraffe as one species. It is hoped that this updated information will soon be taken into consideration by the IUCN for future conservation assessments.

In December 2016 giraffe (as a single species) were uplisted to ‘Vulnerable’ to extinction on the IUCN Red List of Threatened Species. Two subspecies are currently listed as ‘Endangered’.

CITES

Evolution

At about 3 metres tall, an antelope-like animal, which roamed the plains and forests of Asia and Europe between the Eocene and Oligocene epochs (specifically 30-50 million years ago), was the forefather of the two remaining members of the Giraffidae family: the modern day giraffe and okapi.

In countries ranging from Japan, China and Mongolia, through India and Iran and into Greece and Austria, as well as Africa, more than 10 fossil genera have been discovered telling us that by the Miocene epoch (6-23 million years ago) early deer-like giraffids were yet to develop the long neck synonymous with today’s giraffe. They were, however, already tall animals and their heads were adorned with large ossicones (horns made of ossified cartilage, covered in skin or fur), which later began to evolve into the more familiar unbranched ossicones of the modern day giraffids. The end of the Pliocene epoch (2.5-6 million years ago) saw a number of long necked giraffids evolve, but largely unsuccessfully with only two species surviving to this day.

Taxonomy

Giraffe

Okapi

Kingdom:

Animalia

Animalia

Phylum:

Chordata

Chordata

Class:

Mammalia

Mammalia

Order:

Artiodactyla

Artiodactyla

Family:

Giraffidae

Giraffidae

Genus:

Giraffa

Okapia

Species:

G. camelopardalis

O. johnstoni

(Linnaeus, 1758)

(Sclater, 1901)

* Recent research has shown that there are indeed four distinct giraffe species and not only one: Giraffa camelopardalis, Giraffa giraffa, Giraffa reticulata and Giraffa tippelskirchi. Read more about the four giraffe species here.

The modern day giraffe, an even toed ungulate (the same as cattle, camels, sheep, goats and even hippopotamus – but not horses), is the world’s tallest animal and largest ruminant (animals that partly digest their food and then regurgitate it to chew as ‘cud’).

But is there just one ‘giraffe species’ or are there many?

Recent research by GCF and partners has shown that there are four distinct species of giraffe in Africa. Two of these species have two and three subspecies respectively. All species and subspecies live in geographically distinct areas across Africa and while some of the species/subspecies have been reported to cross-bread in zoos, there is little to no evidence that this occurring in the wild.

These recent findings are based on a long-term effort, spearheaded by GCF in collaboration with BiK-F Senckenberg Museum, Frankfurt, Germany and partners, to unravel the mystery of giraffe genetics. GCF and partners collected almost 200 DNA samples from most major giraffe populations across Africa. These new finding will inform the future of giraffe conservation throughout Africa.

The only close relative of the giraffe is the okapi (Okapia johnstoni).

The okapi has a similar body shape as a giraffe, however, with a much shorter neck relative to its body size. Okapis share other distinctive features with giraffe including unusual fur covered ossicones (horn-like structure), specialised teeth and tongue, and a ruminating four-chambered stomach. Interestingly, only the male okapi has ossicones.

The rare okapi is listed as ‘Endangered’ on the IUCN RedList and is endemic to the forests of the Democratic Republic of Congo. The primary strongholds of okapi include the Ituri/Aruwimi and adjacent Nepoko basin forests, and the forests of the upper Lindi, Maiko and Tshobo Basins; the species is also known to occur in the Rubi-Tele region in Bas Uele.

Living in these dark, dense tropical forests the okapi has relatively poor vision but sharp hearing and a good sense of smell. It is extremely wary and will disappear into thick cover at the first hint of danger. Probably for this reason it was only discovered in 1901.

There is no reliable estimate of current population size, but numbers are estimate at between 10,000 and 20,000 individuals. Numbers are assumed to be declining and okapi are under considerable threat due to increased logging and human settlements.

It has been nicknamed the ‘rainforest zebra’ (or ‘forest giraffe’) because of the black and white stripes on its buttocks and upper legs. The stripes on the rump probably act as a ‘follow me’ signal and allow a young okapi to keep track of its mother.

What is the gestation period of a giraffe?

The average gestation period for giraffe is 453-464 days or approximately 15 months.

Where and when do giraffe give birth?

While there have been reports that giraffe have given birth in a ‘calving ground’ and that mothers have been observed to return to where they were born to have their own babies, this needs further verification and research.

Giraffe have no formal breeding seasons as they are designed to be able to shift feeding patterns in order to maintain a high nutrient diet throughout most of the year. It has been observed that calving can be synchronised in herds to provide safety in numbers against predators.

Giraffe give birth standing up, requiring the newborn to fall just under 2 metres (6 feet) to the ground! Designed for such an abrupt entry into the world, a newborn calf can stand up and run within an hour of being born.

What is a baby giraffe called?

A baby giraffe is called a ‘calf’.

How big are giraffe calves at birth?

The average height at birth is just under 2 metres (6 foot) with a tendency for the females to be slightly smaller than the males. A newborn calf weighs about 100 kilograms. Newborn calves grow very quickly and can nearly double their height in the first year. Usually a giraffe will only have one calf although twins have been recorded.

For how long will a giraffe rely on its mother’s milk?

A newborn giraffe will suckle its mother’s milk as soon as it can stand up – that’s why they are so tall at birth. Calves are reliant on their mother’s milk for up to 9-12 months. Solid food (leaves) are eaten from about 4 months at which time calves begin to ruminate.

What is the biggest threat to a baby giraffe and how can a mother protect her calf?

The first few months of a giraffe’s life are the most vulnerable; predators such as lions, hyenas, wild dogs, crocodiles and leopards all see a baby giraffe as prey. Giraffe mothers are extremely protective and will meter out a powerful kick to any other animal that comes too close. During the first few days a newborn giraffe will often be left sitting in high grass, while the mother goes off to feed, but after a few weeks the youngster is introduced to the rest of the herd. Nursery groups, where one mother will keep watch while the others have a chance to go and find food, have been observed in the wild.

When do giraffe ‘leave home’?

Male calves will leave their mothers from about 15 months and often join all-male groups. The female juveniles, however, often stay in the same herd as their mothers or if they do leave then do so about 18 months old and often stay in the same areas as the family herd they grew up in.

We don’t really know how long giraffe live in the wild as there is no recorded evidence. We believe that both male (bulls) and female (cows) giraffe can live to about 25 years in the wild and even longer in captivity. In our long-term conservation project in northwest Namibia we now know that some giraffe that were first identified as sub-adults in 2000, are still alive today – making them some of the oldest recorded giraffe in the wild.

However, even the world’s tallest animal has enemies. Giraffe mortality rates vary from region to region dependent on density of natural predators. Even adult male giraffe are predated by lions, while sub-adults and calves are particularly vulnerable and can also be taken by hyena, leopard, wild dog and crocodile.

As an example, the infant mortality rate in the Serengeti (Masai giraffe – G. c. tippelskirchi) for one month old giraffe calves is over 20% while approximately half of the calves do not survive their first 6 months. This figure reaches nearly 60% by the end of the first year in the Serengeti, dropping to 8% in the second year and just 3% in the third.

Once mature, the defensive kick of an adult giraffe is enough to seriously damage even the most determined predator, and many a lion has succumbed to the fierceness of their dinner plate size hooves.

Where water is readily available giraffe will often drink, sometimes daily, with splayed forelegs and/or bent knees to enable their long neck to reach down to the water.

However, in the deserts of northwest Namibia and other arid environments, giraffe absorb the majority of their moisture from condensation (and coastal fog) that gathers and is absorbed from the leaves during the much cooler nights and early mornings, or from coastal fog that covers part of the desert on two out of three nights.

Giraffe are browsers and mainly eat leaves and buds on trees and shrubs. They will also eat herbs, climbers and vines, and prefer flowers and fruit when in season. The proportion of grass in their diet is very low. Acacia leaves and shoots form the bulk of a giraffe’s diet in most areas.

Giraffe use their extremely dexterous and long tongue as well as the ridged roof of their mouth to help feed on a variety of leaves and shoots – all dependent on the plants defenses!

Evidence shows that giraffe adapt their diet to the food species available in the specific region they live in, as well as adapting intake depending on seasons and plant growth stage; for example in some parts of Southern and Eastern Africa, giraffe often feed on deciduous trees, shrubs and vines during the wet season, and on evergreen species, near streams and rivers, during the dry season.

Males are capable of feeding on vegetation at higher levels than females, although both can stretch their head and neck near vertical to access preferred forage. Scientists have found that the diet of adult females is nutritionally richer than that of males who consume significantly higher proportions of fibre and lignin. Giraffe appear sensitive to their own nutritional needs. For example, in Niger nursing females seem to avoid high levels of tannins in leaves even though it means giving up higher quality forage.

Regardless of their size, giraffe are not as destructive as elephant when feeding, indeed one researcher in the Serengeti, Tanzania, demonstrated that when giraffe are not too numerous, their impact can actually stimulate shoot production in Acacia species, which soon declined when the browsing stimulus was withdrawn. There are, however, also some natural plant protection methods at work which ensure over-browsing does not happen. For example carnivorous ants that are symbiotic with some Acacia species reduce the amount of time that giraffe can spend browsing on any one plant.

On a positive mutual note, giraffe can actively benefit some of their food sources. Acacia seed consumption by giraffe favours seed dispersal into non-shaded habitats and enhances the potential for seed germination through the beneficial effects of its digestive processes. Giraffe are also thought to play a role in pollination.

Feeding takes up most of a giraffe’s day – up to 75% at certain times of the year. Time spent browsing often increases markedly during the dry season compared with the wet season as good quality browsing is harder to find and giraffe often have to travel further to satisfy their nutritional needs. Giraffe are also active at night, but it is believed that they feed significantly more during moonlit nights and ruminate more during dark nights.

One of the distinguishing characteristics of a giraffe is its long neck. The neck has several important roles and specific functions:

Feeding

With the aid of its long neck, a giraffe is able to reach leaves, fruit and flowers high up in Acacia’s and other sought after tree species. Giraffe are thus equipped to exploit a band of foliage beyond the reach of all other terrestrial browsers, except for elephant. Their 45 cm long tongue combined with a modified atlas-axis joint that lets the head extend vertically, further increases the height advantage. Giraffe can browse the crowns of small trees; big bulls can reach higher than cows. Giraffe feed mainly on broad leaved deciduous foliage in the rains and on evergreen species in other seasons.

Necking

Bulls, although also cows have been observed, have developed an elaborate ritualised fight called ‘necking’ that helps to most likely establish dominance. They repeatedly swing their long neck to deliver powerful head-butts to their rival’s body and underbelly. A reinforced skull usually absorbs the impact of these blows, but occasionally an animal is knocked unconscious and very rarely even dies during such a fight.

Lookout

The giraffe’s height also helps it to keep a sharp lookout for predators across the wide expanse of the African savanna, essentially a tall ‘sentinel’.

Blood Supply

A giraffe’s heart, which can weigh up to 11 kilograms, has to generate almost double the normal blood pressure of other mammals in order to maintain blood flow to the brain against gravity. In the upper neck, a complex pressure-regulation system called the the rete miribale prevents excess blood flow to the brain, when the giraffe lowers its head to drink. Conversely, the blood vessels in the lower legs are under great pressure (because of the weight of fluid pressing down on them). In other animals, such pressure would force the blood out through the capillary walls. Giraffe, however, have a very tight sheath of thick skin over their lower limbs which maintains high extravascular pressure in exactly the same way as a pilot’s G-suit.

Structure

Surprisingly, even with its long neck, the giraffe has the same number of vertebrae in its neck as humans and other mammals. Giraffe have seven cervical vertebrae, but each one can be about 25 cm long.

Giraffe ‘horns’ are not actually called horns but ‘ossicones’ and both female and male giraffe have them. Ossicones are formed from ossified cartilage and are covered in skin.

Giraffe are born with their ossicones, however, they lie flat and are not attached to the skull to avoid injury at birth. They only fuse with the skull later in life.

Both female and male giraffe have a main pair of ossicones. While the females’ are often thin and tufted, male giraffe normally have thicker ossicones that become bald on top as a result of frequent necking. In some subspecies males grow a second pair of ossicones behind the first pair, as well as prominent ossicone in front of the main pair.

Ossifications on the head of male giraffe add weight, which often increases with age enabling them to deliver ever heavier blows during necking contests. Fatal combat is rare but does occur.

Giraffe’s patches (spots) are first and foremost for camouflage. But underneath each patch lies a very sophisticated system of blood vessels. Around each patch there is a quite large blood vessel that then branches off into smaller vessels underneath the patch:

A giraffe can send blood through these small branches into the middle of the patch in order to release heat through this system. Each patch acts as a thermal window to release body heat.

The left image below shows the patches of a giraffe and the one on the right shows the intensity of heat radiation. You can see that the patch pattern corresponds directly with the heat radiation patter on the body of the giraffe.

Giraffe use their 45-50 cm long prehensile tongue and the roof of their mouths in order to feed on a range of different plants and shoots, most notably from Acacia species.

Africa’s Acacia species have developed fierce defensive thorns, requiring giraffe to use their dexterous tongues to sort out the nutritious leaves from spiky thorns. Fortunately, a giraffe’s tongue has thickened papillae, which helps to protect it from these vicious thorns. Additionally, thick saliva is also believed to help protect giraffe’s tongue and mouth against the defensive mechanisms of their favourite food.

The colour of the tongue is best described as black, blue or purple with a pink base/back (see photo below). It is generally assumed that the front part of the tongue has such dark coloration to protect it during frequent sun exposure while eating and prevent the tongue from getting sunburned, however, no one really knows.

The giraffe has an extremely high blood pressure (280/180 mm Hg), which is twice that found in humans. Additionally, the heart beats up to 170 times per minute. That is double the heart beat of humans. It was previously thought that a giraffe had a really big heart, but recent research has revealed that there isn’t room in the body cavity for this. Instead, the giraffe has a relatively small heart and its power comes from a very strong beat as a result of the incredibly thick walls of the left ventricle (Image from BBC 4 “Inside Nature’s Giants – Giraffe”)

Cross section of the giraffe’s heart

the left ventricle showing the right ventricle showing the

the very thick muscle wall much smaller muscle wall

The right ventricle pumps the blood a short distance to the lungs, and the muscle is about 1cm thick.

The left ventricle has to pump the blood all the way up to the head against the hydrostatic pressure of the blood already in the long vertical artery. A giraffe’s heart has evolved to have thick muscle walls and a small radius giving it great power to overcome this pressure.

The thickness of the muscle wall is related almost directly to the length of the neck. For every 15 cm increase in the length of the neck the left ventricle wall adds another 0.5 cm thickness.

Giraffe normally rest while standing up, but sometimes they can be observed lying down. When lying down, they fold their legs under their body, but mostly keeping their necks held high. Giraffe have been known to continue browsing and ruminating in this resting position.

Occasionally, and only for very short periods of no more than 5 minutes, giraffe can sleep with their head resting back on their rump. This is an extremely exposed and vulnerable position, hence the brevity and rarity. Research in zoos has shown that giraffe go into REM sleep when in this position.

Just like human fingerprints, no two giraffe have the same coat pattern.

Giraffe feet are the size of a dinner place with a diameter of 30 cm.

Giraffe tongues are bluish-purple and between 45-50 cm long.

Both male and female giraffe have ‘horns’ already at birth. These ossicones lie flat and are not attached to the skull to avoid injury at birth. They only fuse with the skull later in life.

The giraffe is the tallest mammal in the world. Even newborn giraffe are taller than most humans.

Female giraffe give birth standing up. Their young fall about 2m to the ground and can stand up within an hour of birth.

About 50% of all giraffe calves do not survive their first year.

A giraffe’s neck is too short to reach the ground. As a result, it has to awkwardly spread its front legs or kneel to reach the ground for a drink of water.

Giraffe only need to drink once every few days. Most of their water comes from the plants they eat.

To protect the giraffe’s brain from sudden changes in blood pressure when it lowers its head to drink, it has valves to stop the back-flow of blood and elastic-walled vessels that dilate and constrict to manage flow. NASA has done research on the blood vessels in giraffe legs to get inspiration for human space suits.

A giraffe heart weighs approximately 11 kilograms and is the biggest of any land mammal. It is used to pump 60 litres of blood around its body every minute at a blood pressure twice that of an average human.